From patent specification EP 0 706 968 A2 a drive unit for an elevator has become known. The drive unit has passing through it a shaft which serves both as the shaft for a motor and a shaft for a gear. Arranged at one end of the shaft is a gear with a traction sheave for the elevator rope. Attached to the free, motor end of the shaft is a handwheel for emergency operation of the drive unit.
Fastened by pivoted joints to a baseplate are arms which carry brake shoes. By means of a cylinder, the brake shoes are pressed against the external circumference of a braking body.
A disadvantage of the known device is that the handwheel is situated close to the motor. When the handwheel is turned, fingers can easily be caught and trapped by the rotating handwheel. For emergency operation, the brake must be released at the same time as the handwheel is turned. Releasing the brake is made difficult by the brake being situated at one end of the motor and the handwheel at the other end.
In the case of gearless machines, the forces which must be overcome for emergency operation are substantially greater. To overcome them, it is common to use a gearbox with a handwheel, the gearbox being connected to the main shaft by means of a coupling device. Such equipment is expensive, awkward, and not without danger in operation.